Residents in Leamington Spa are being evacuated after reports of explosions in a large blaze at an industrial premises.
A plume of thick smoke could be seen rising above the fire on Juno Drive on an industrial estate in the Warwickshire town.
Police were evacuating people from nearby properties, Warwickshire police said.
Warwickshire fire service said it was called at 10.39am on Friday to a large building fire and urged people living within 70 metres of the area to keep doors and windows closed.
West Midlands ambulance service also confirmed it had sent two paramedic officers and its hazardous area response team to the scene.
Public Health England issued a warning saying the smoke and ash from the fire could worsen health problems such as asthma and heart conditions, and advised people to stay away and carry their medication if nearby.
Road closures are also in place.